I guess you will be seeing the Doctor before long , let us know what it is ,I know fire ants can hurt a lot if they sting, they come up to a head they hurt and they itch, they are small also liquid does come out of them , they can last a few days .Did you notice a time frame when it appeared 3 days ago was it after he had been out playing in the garden?,
no he says it hurts. It has scabbed over since we put the ointment on it so that's good. He hasn't gotten bigger today but it is still the same dime size.
Perhaps he was bitten by a bug ,I understand your concern and if he doesnt feel well or it looks worse I would get it looked at, if not tomorrow would be okay .Has he had any symptoms other than the itch ?